<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    
</body>
<script>
    var arr =[
        {label:'1',children:[{label:'10'},{label:'11',
        children:[{label:'10'},{label:'11',children:[{label:'10'},{label:'11'}]}]}]},
        {label:'2'},
        {label:'3'}
    ]
    function transform(list) {
    if (Array.isArray(list) && list.length !== 0) {
        list = list.map(v => {
            v.label = Number(v.label) + '%'
            if (!transform(v.children)) {
                // v.isLeaf = true
            }
            return v
        })
        return list
    } 
    }

console.log(transform(arr))
</script>
</html>